Because most power sources have a limited range of output RPM, machines employing such power sources will also typically employ a multispeed transmission to provide a greater range of machine speed. One type of multispeed transmission is the planetary transmission. Such a transmission generally includes many planetary gear sets linked together in various ways, with selectable elements used to select the input/output ratio.
However, planetary gear sets take up a significant amount of space, and it is typically required to either settle for a limited number of gear ranges or allow for a greater installation footprint to include a greater number of planetary gear sets. For example, U.S. Pat. No. 7,963,876 to Phillips minimizes the number of planetary gear sets used, but also provides only three reverse speeds. The transmission described in the Phillips patent includes four planetary gear sets and various clutches and brakes. The clutches and brakes are selectively engageable to provide different speed ratios, but only three reverse speed ratios are enabled. Thus, while up to seven forward speeds are shown, fewer than half as many reverse ratios are available within the Phillips system.
The present disclosure is directed to a system that addresses one or more of the problems set forth above. However, it should be appreciated that the solution of any particular problem is not a limitation on the scope of this disclosure nor of the attached claims except to the extent expressly noted. Additionally, the inclusion of any problem or solution in this Background section is not an indication that the problem or solution represents known prior art except as otherwise expressly noted.